Fiorentina underlined their credentials to challenge for a European place this season as they upset defending champions Napoli 3-1 at the Stadio Diego Armando Maradona.

Although Victor Osimhen’s penalty in first-half stoppage time cancelled out an early strike from Josip Brekalo, Napoli had no answer after Giacomo Bonaventura restored Fiorentina’s lead in the 63rd minute, with substitute Nicolas Gonzalez adding a late third.

The result sees Fiorentina move level with Napoli on 14 points, seven behind early pace-setters AC Milan.

Fiorentina started brightly, with Lucas Martinez seeing an ambitious early overhead kick effort blocked, and those endeavours were rewarded when they took the lead with seven minutes gone.

It was Martinez again who saw his rather awkward effort off his knee bounce back off the post, but it fell for Brekalo to slot it through the goalkeeper’s legs from a tight angle.

Napoli’s desire to make amends saw them pour forward but too many of their moves were rushed, the ball pinging about on the edge of the Fiorentina box in a manner they could not control.

A chaotic move saw the ball in the back of the net after 22 minutes but they were denied an equaliser by the assistant’s flag.

Osimhen’s shot was blocked but Matteo Politano’s disguised pass found Khvicha Kvaratskhelia. Fiorentina again got in a block and Mathias Olivera was offside when he sent in a cross-cum-shot that was tucked in by Osimhen at the far post.

They kept coming forward, but Pietro Terracciano made a fine save to keep out Stanislav Lobotka’s powerful drive.

Osimhen’s penalty appeals were in vain when he was bundled over late in the first half, but the officials could not ignore him in stoppage time when Fabiano Parisi’s chested pass back to Terracciano fell short and the goalkeeper collided with the advancing striker.

And, having put himself back on penalty duty, Osimhen dispatched a powerful shot from the spot.

Fiorentina nearly got back in front five minutes into the second half when Jonathan Ikone’s shot struck the right-hand post.

It was end-to-end at this point – Osimhen sent a shot across goal for Napoli, then Ikone narrowly missed the target through a crowded box.

Osimhen should have put the hosts in front just before the hour when he broke away down the left but he was too slow to shoot and Terracciano cut off the angle.

And Fiorentina made him pay for the missed opportunity as the visitors retook the lead moments later. Alfred Duncan ran into trouble but the ball bounced for Bonaventura, left in far too much space on the penalty spot, and he tucked the ball away.

Napoli pushed for an equaliser but it would be Fiorentina celebrating at the end as they hit their hosts on the counter attack in stoppage time, with Gonzalez finishing the move.